The present invention generally pertains to a system for limiting power dissipation in a power transistor to less than a destructive level.
Destructive secondary breakdown in a power transistor occurs when the power being dissipated by the power emitter causes the temperature of the emitter to rise to a destructive level. The destructive power dissipation level in a power transistor is not easily calculated and/or may vary considerably between power transistors even though they have the same nominal power rating. To prevent destruction of power transistors it has been necessary to rate the operation of power transistors considerably below their capabilities.